---
layout: example
category: example
title: Animate a point
description: Animate the position of a point by updating a GeoJSON source on each frame.
---
<div id='map'></div>
<script>
var map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/mapbox/streets-v8',
    center: [0, 0],
    zoom: 2
});

var radius = 20;

function pointOnCircle(angle) {
    return {
        "type": "Point",
        "coordinates": [
            Math.cos(angle) * radius,
            Math.sin(angle) * radius
        ]
    };
}

map.on('load', function () {
    // Add a source and layer displaying a point which will be animated in a circle.
    map.addSource('point', {
        "type": "geojson",
        "data": pointOnCircle(0)
    });

    map.addLayer({
        "id": "point",
        "source": "point",
        "type": "circle",
        "paint": {
            "circle-radius": 10,
            "circle-color": "#007cbf"
        }
    });

    function animateMarker(timestamp) {
        // Update the data to a new position based on the animation timestamp. The
        // divisor in the expression `timestamp / 1000` controls the animation speed.
        map.getSource('point').setData(pointOnCircle(timestamp / 1000));

        // Request the next frame of the animation.
        requestAnimationFrame(animateMarker);
    }

    // Start the animation.
    animateMarker(0);
});
</script>
